Place parmesan into the Thermomix bowl and mill 10 sec/speed 10. Set aside.
Place onion, garlic and EVOO into the Thermomix bowl and chop 3 sec/speed 5. Saute 5 min/Varoma/speed 1.
Add rice and wine and saute 2 min/Varoma/Reverse/speed 1.5.
Add stock and cook 16 min/100/Reverse/speed 1.5.
Meanwhile, brown butter to nut brown stage in a pan and fry mushrooms till tender. Keep hot.
When risotto has finished cooking, stir through parmesan.
Serve, topped with mushrooms and garnish with thyme leaves.